What’s the Best Time of Day to Exercise? The Fitness Pros Weigh In

Some exercise routines are more regimented than others: We all know that devoted 5:00 a.m. runner, the regular 2:00 p.m. doubles player, the 7:00 p.m. yoga fanatic. But which of these time frames, if any, provides the best workout? Los Angeles–based private Pilates trainer Nonna Gleyzer—Gisele Bündchen and Kerry Washington have logged hours on her Reformers—points out the benefits of moving in the morning: “It’s a wake-up call for your body instead of a coffee full of sugar,” she says.

Sure, extra sleep is restorative, but an early run kick-starts blood circulation, and the accompanying endorphin rush brightens moods. Afternoon activity, however, can regulate circadian rhythms, and is essential for weight loss. And evening workouts offer huge hidden benefits, too: Trainer Paul Vincent, cofounder of Santa Monica, California’s Altus Sports Institute, says some night exercisers can “push themselves hard in their workouts, become very restful in recovery, and flush out stress before sleeping.”

Here, a primer on the pros and cons of different times for exercise—as well as the best workout approaches for each.

MorningA sunrise ballet class or jog is a speedy detox, flushing out the liver first thing in the morning. It’s also a great way to log gym time before starting the day. But Vincent warns the crack-of-dawn crowd to warm up before plunging into a heart-pumping workout. “Keep in mind that because you’ve been lying down in a sleep state for several hours, it’s important to take time to prepare your body for exercising,” he says. Gleyzer favors slower, simple moves before any major stretching. “Give your body a chance to align itself, and be aware of seasonal weather to avoid extreme changes in temperature,” she says. In other words, if a room is hot but it’s cold outside, be careful not to overstretch, as muscles can contract and spasm when you leave the studio. Similarly, when your body is warm on a hot day, if you walk into an air-conditioned room, muscles can get hard and stiff to protect themselves against the sudden chill.

AfternoonAn afternoon Spin session can rev up a resting metabolism—Gleyzer says it’s the most important workout of the day for weight loss, especially when it comprises part of a two-sessions-a-day plan. “Dancers and NFL players alike train in the afternoon, in addition to morning sessions,” she says. “If you don’t have time during the week, just do it on the weekend.” Vincent agrees that scheduling is the hardest part of an afternoon workout. And yet a groundbreaking 2012 study conducted by the University of California, Los Angeles’s Brain Research Institute found that mice who exercised around midday had sturdier circadian rhythms. (Out-of-sync rhythms have been linked to diabetes, obesity, cancer, and depression.) Mice who hit running wheels in the morning and in the evening also benefited, but afternoon joggers produced more of the proteins that aid body clock regulation.

EveningA 10-mile run followed by a large takeout order late in the evening can delay the onset of sleep—a wellness no-no. Intense Spinning with loud music or heavy weights can also disrupt rest. “Although, if you’re the type who can drink coffee and go to sleep, then go for it,” Gleyzer says. She instead recommends what she calls “happy medium” sessions of Pilates, yoga, relaxed tennis, or swimming. Evening power walks, she points out, also function as antidepressants, quickly releasing anxiety and stress accumulated during the day. Vincent agrees that evening exercisers should be mindful not to increase energy levels when bodies should be shutting down: “But it can help clear your mind before falling asleep,” he says. Mice in the UCLA study developed disrupted circadian rhythms when burning calories after 11:00 p.m., a logical reason to avoid taking full advantage of 24-hour gyms. These issues aside, both Vincent and Gleyzer agree that squeezing in a workout, whenever you can, will ultimately benefit your body. “Just do it in a smart way,” Gleyzer advises. ”Know what to do at which part of the day.”